Chromosomal studies were conducted on 38 white rhinoceroses representing both the northern and southern subspecies and one subspecies hybrid. Improvements in tissue culture methods and harvesting techniques have made it possible to obtain a highly repeatable diploid number of 82 chromosomes for both subspecies. Comparison of G-banded karyotypes from the two subspecies failed to indicate a difference in banding pattern, but did reveal size polymorphisms involving short arm additions in five individuals. Chromosomal polymorphism, resulting in three individuals with a diploid number of 2n = 81, was noted in northern white rhinoceroses.